JP2739578B2 - Method of controlling the temperature of a member having an electric resistor - Google Patents

Abstract

The invention relates to the conducting and to the monitoring, using an automatic machine, of the temperature rise of electrically heated components with which there is associated an identification chart comprising parameters which can be used for conducting and for monitoring this heating, the machine comprising apparatus for reading the chart and for initiating the determined heating program. According to the invention, the chart is divided into a number of zones into some of which are entered, in addition to the said parameters, additional data concerning some of them, the parameters and their associated data are read off using the said reading apparatus, and provision is made for at least some of these parameters to undergo conversions which are induced by some of the other associated zones as a function at least of the data which are contained therein. The invention applies particularly to the monitoring of welding together of plastic components.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling a temperature rise of an electrically heated member by an automatic controller. The method according to the invention makes it possible in particular to automatically weld the plastic parts to one another. BACKGROUND OF THE INVENTION For example, in the field of gas supply, plastic pipes are actually increasingly used, especially for the preparation of piping systems, which leads to problems with the connection of the pipes to one another. In fact, the pipe is not suitable for gluing, so that it is necessary to weld the pipe in order to achieve a sufficient connection that satisfies all the required safety conditions. However, many manufacturers currently market such components, especially those made of plastic (eg, polyethylene), for such bonding. In fact, each manufacturer has established proper rules for welding parts under better conditions. Therefore, users who use materials from different manufacturers or materials of the same manufacturer but of different types must modify or adapt the welding standards depending on the type of material used. To control the temperature of the material, regardless of the type of material used, so that welding is possible, and more generally, a specific card containing parameters useful for control is already placed on the controlled member, A method has been proposed in which the controller is provided with means for reading the card and means for realizing a heating program controlled depending on the parameters read by the automatic controller. Such a method substantially corresponds to the method of French patent application No. 84-16691 filed on Oct. 31, 1984 by the applicant. The method and apparatus described in the above application effectively avoids the problems associated with the inflexible provisions of the list of materials provided and the specifications of each designer, and the components are comprehensive at the level of use. Is specified. However, the method and apparatus described above
It is for automatically welding plastic materials to each other. SUMMARY OF THE INVENTION The method according to the invention can be used for this kind of purpose to provide the same advantages, and more generally, to exactly adapt the above parameters depending on the actual conditions of use. By doing so, parameters useful for managing the heating of the member can be determined and controlled. More specifically, the present invention divides a particular card of a member into a plurality of independent zones, and provides at least some of the zones with at least some of the at least one parameter in addition to the control parameters. Auxiliary information including the following information is input, and parameters and / or information included in the zones are successively taken out of each zone in a predetermined order by the reading means, and at least some of the parameters read from the corresponding zone are read out. On the other hand, it is characterized in that the correction induced from at least a part of another related zone depending on the auxiliary information included in the zone is performed. The advantages of the method according to the invention will be clear from the examples. When the invention is applied to the welding of two plastic pipes, the pipes are joined using a sleeve containing an electric coil on the inner surface. In this case, the welding operation consists of connecting the coil to a power supply and heating and melting the plastic material of the sleeve and pipe. Now consider the parameter "resistance of the sleeve R" (this parameter and its associated value specified by the manufacturer are entered in at least one predetermined zone of the card). In practice, the numerical values of the above parameters essentially depend on two criteria: the manufacturing tolerances of the resistive element of the sleeve and the temperature-dependent change of the ohmic value related to the properties of the resistive wire. In fact, these two criteria are the average reference temperature (eg,
20 ° C), which affects the theoretical ohmic value of the sleeve when placed in an atmosphere at a different temperature. Now, the numerical value of the parameter “resistance” indicated in the corresponding zone of the card corresponds to the above theoretical ohmic value. In order to "correct" the resistance value to be taken into account by means of implementing the control and heating program of the device, the method determines the tolerance tolerance depending on the combined action of the two criteria. The determined tolerance is also input to a predetermined zone of the card, for example, in a form corresponding to the% of the allowable error, and compares the theoretical resistance value at 20 ° C with the actual resistance value under the actual heating and control conditions. When doing so, consider. This actual value can be supplied and input to the analog / logic stage of the device by means other than a card (e.g., sonde, sensor) for some parameters. In connection with the above example, the method according to the present invention actually comprises external means independent of the card for directly extracting from the member at least one parameter useful for inducing and controlling the heating of said member. Means for inputting the auxiliary parameters to the device, further comprising, based on the method, at least some of the parameters input to the card as reference parameters, and depending on the numerical values of the extracted auxiliary parameters, The included auxiliary information is applied to the relevant reference parameters to supply correction parameters for taking into account the actual conditions to the means for implementing the control / heating program of the device. [Examples] The present invention described below will be described more clearly. The method according to the invention is particularly suitable for controlling and welding two parts together, and the invention will be described below with reference to this example. At the outset, it has already been mentioned that two elements (for example polyethylene pipe) can be joined by straddling the two butt ends of the two pipes and also welding a polyethylene sleeve. . The end of the electric coil of the sleeve can be operated in the usual manner from two feed terminals. As described in the above-mentioned French patent application No. 84-16691, a temperature rise suitable for achieving good welding of the two pipes and the sleeve essentially depends on the characteristics of the sleeve, in particular the sleeve diameter, the sleeve wall thickness, Depends on the resistance of the built-in electric coil, etc. All of the above parameters, which indicate the conditions for performing the welding program, i.e. the heating and heating control, which essentially depend on the duration and power of the electric heating, are indicated on a specific plate or card mounted on the sleeve. This particular plate may in particular be of the type of a bar code (readable by an optical pen or laser). The above-mentioned French patent uses an optical pen connected to an analog logic stage that can introduce specific data into the device.
In this way, the parameters (data) of the specific plate (card) arranged on the sleeve (that is, the component) are read by an optical pen or the like and input to the control device. Further, external means for obtaining auxiliary parameters are provided.
This external means consists of a thermal probe which includes a temperature sensor which senses the actual effective temperature of the sleeve or member at the start of welding. The thermal probe is connected to the control device so that the above-mentioned auxiliary parameters can be introduced into the processing stages of the control device. In this way, auxiliary parameters for the temperature of the sleeve (or part) at the start of the heating process are input to the controller. The means for implementing the welding program (ie controlled heating) consist of a program circuit which can determine the welding program to be performed depending on the parameters from the specific card and the auxiliary parameters (data) from the thermal probe. The welding program adjusts the welding power supply connected to the processing stage to apply the required predetermined electrical energy to the workpiece. The method according to the invention, when applied to the welding described above, uses the means and the general structure provided in the device to which the earlier application is directed, but this is not the object of the invention, but in detail No explanation. However, if necessary, reference is made to the above application. Relying on the above means, the method according to the invention divides the card attached to the member to be heated into a plurality of independent zones, wherein at least one of said zones contains the parameters useful for controlling heating. In addition to the above, correction information related to the above-mentioned parameters and operable is also input. This correction information is information for making a correction in the calculation of the heating power, as can be understood from the detailed description of the zone 8 described later. (For example, if the component temperature is
No correction is made at 20 ° C, but if it is lower than 20 ° C, a positive correction percentage is determined, and if it exceeds 20 ° C, a positive correction percentage is determined. Then, the parameters and the correction information included in each zone are successively taken out in a predetermined order by an optical pen. Further, correction or correction is performed by applying the correction information input to the card to related parameters including auxiliary parameters. Here, at least one of the parameters (for example, the theoretical resistance value of the member) is regarded as a reference parameter, and with respect to this reference parameter, based on the correction information and auxiliary parameters (for example, actual resistance value or actual resistance value). The correction is performed depending on the temperature. Thus, the parameters used to calculate the heating power are modified and provided to the controller. In fact, the parameters controlled are the heating power used,
It consists of supply current, supply voltage, heating time, theoretical and / or actual temperature of the controlled member. For ease of explanation, the structure of a specific card that can be used and the general functional principle will be described as an example. The identification card in question is of the barcode type with 24 characters and can be read by a manual optical pen. The controlled parameters are the voltage, current or power of the electric heating, the heating time and the temperature of the member. The 24 characters included in a particular card are divided into nine independent major zones. The first zone contains the first eight characters, on the one hand the reference of the component maker can be defined, on the other hand the information or external parameters contained on the card (for example the temperature detected by the sonde).
, Auxiliary information useful for identification of components, control, and selection of a parameter correction method can be input. The second zone includes three characters that determine the diameter of the member. The third zone contains one character and defines the type of adjustment determined by the component designer. This adjustment depends on the voltage,
It can be implemented by controlling current or power. The numerical value of the character further defines a unit for taking into account the theoretical numerical value of a predetermined parameter of the heated member (the sleeve in this case) in the device. The fourth zone includes two characters that can be rated for the adjustments described above. The fifth zone corresponds to the mean value of the parameters obtained during manufacture or the theoretical value which helps to establish the actual control value,
Includes three characters that are effectively utilized by the program of the device to identify certain parameters of the sleeve. (This point will be described below.) In short, it is considered that the above-mentioned zone determines the numerical value of the characteristic of the sleeve defined in the third zone. In this case, the above features replace the reference parameters. The sixth zone includes one character that defines a correction factor. Thus, this correction factor constitutes the auxiliary information entered in the card and is written to the fifth zone depending on the auxiliary parameters calculated by the calculation unit or the external parameters supplied from the thermal probe in this case. "Modify" the values of the parameters entered. The seventh zone includes three characters and defines a predetermined heating time. In the present case, this time is given in seconds or minutes. The eighth zone includes two characters that define a correction to the time, voltage or power of heating depending on the temperature of the component (calculated or sensed by a thermal probe). Finally, the ninth zone contains, in a manner known per se, only one character having a numerical value that is key to a good reading of the control or card. Therefore, as is apparent from the above description of the construction of the card, the characteristics of the member or the predetermined parameters can be ascertained, the energy supplied from the power supply used to heat the member to the appropriate desired temperature or the member can be modified. An application can be made. Now, the configuration of each zone of the card and the principle of its interaction will be described in detail. First Zone The eight characters in this zone can represent: 1. Manufacturer's reference number represented by two numbers. The origin of the used material can be confirmed by the reference number of the manufacturer. 2. Each of the odd characters, ie, the first, third, fifth, and seventh characters, has an auxiliary information on the card by adding any predetermined value selected equal to 0, 3, or 6 to that character. Can be entered. In this case, the first character determines the type of the member to be used (sleeve, pipe,...), And the third character is
The parameters to be modified (e.g., the heating period, the power supplied from the power supply) depend on other parameters, in particular the component temperature given by the sound, and the fifth character defines the nature of the welding cycle. The fifth character is
In addition, it is possible to supply auxiliary information that can act on a predetermined parameter (see the 18th character in the sixth zone). The seventh character defines a temperature range determined by the designer. Examples 1st character coded information value added to the relevant character character 0 = grip or saddle 3 = sleeve or socket 6 = electrical heating accessory other than electric welding 3rd character information value added 0 = time correction U (voltage) or I (power supply) adjusted with power 3 = U or I adjusted with power correction 6 = adjustment of power Fifth character Information value added 0 = uniform welding cycle 3 = another cycle 6 = Information value to be added to the seventh cycle of another cycle 0 = First temperature range specified by member manufacturer 3 = Second temperature range 6 = Third temperature range Accordingly, three types of barcodes are provided in the first zone. You can enter auxiliary information. Example Manufacturer LINO GAZ Abbreviation LINO The above characters have the following numerical values in coded form. L = 12 I = 09 N = 140 = 15 Now, if the eight combined characters in the first zone form 12391465, the following information is input. Information "grip or saddle" at the level of the first character (add a numerical value "0" to this first character); information U or I "which is adjusted with a correction of the power.
(At the level of the third character plus "3")-Information on the seventh character "uniform welding cycle"
("6" is added to the seventh character). Second Zone The second zone relates to the ninth, tenth, and eleventh characters. The character determines the diameter of the member. In the case of a sleeve, the inscribed diameter corresponds to the outside diameter of the pipe to which the sleeve is to be fitted. Two equally spaced ranges are defined. 1. The diameter of the member is expressed in mm. The numbers that can be used are 001-779. The ninth character indicates a unit of 100 mm. The tenth character indicates a unit of 10 mm. The eleventh character indicates a unit of 1 mm. Example: φ20mm = 020, φ110mm = 110 2. The member diameter is expressed in pus (2.6mm). In this case, the numbers that can be used are 800-999. The ninth character indicates a unit of 10 ps. The tenth character indicates a unit of 1 ps. The eleventh character indicates a fractional push. Based on the code: 0 = integer push 1 = 1/4 push 2 = 3/8 push 3 = 1/2 push 4 = 3/4 push Example: φ1 ″ = 810, φ1 ″ 1/4 = 811 Determine the diameter Number 00 for accessories that cannot
0 can be used. Third Zone 1. For the characters included in the third zone, the correction mode (voltage U, current I, power P) can be determined depending on the information value of the third character in the first zone. The numerical value calculated depending on the correction mode to be selected is entered in the fourth zone. This value is calculated in the calculation unit (see zone 6). In U mode: voltage control in 1 volt steps In I mode: current control in 1 amp steps In P mode: power control from U to calculate power from equation U2 / R Calculate power from equation RI2 Power control from I. 2. The character included in the third zone can indicate the position of the comma of the rated value of the characteristic parameter of the heated heating member. In this case, the characteristic parameter corresponds to the resistance (R) of the member. An example Therefore, when the above parameters are read, the power supply correction mode to be selected is confirmed, and the unit (Ω, 10Ω, 100Ω) of the characteristic parameter to be selected is confirmed. 4th zone U, I or P shown in the 12th character (3rd zone)
Based on the mode, the thirteenth to fourteenth characters in the fourth zone represent the numerical values of the adjustment parameters to be selected. U Mode The numbers entered for the thirteenth and fourteenth characters represent the selected rated effective voltage value that is held constant at the input terminal of the sleeve coil during heating. Example: 35 volts 13th character = 3 14th character = 5 I mode In this case, the numerical values of the 13th and 14th characters represent the selected current value that is kept constant during heating. Example: 4 amps 13th character = 0 14th character = 4 In this case, the unit to be selected is, of course, U for bolt and I for ampere. Power parameters (P, watts) can be considered as well. Fifth Zone The fifth zone includes the fifteenth, sixteenth, and seventeenth characters into which information on the characteristic parameters of the member selected at the level of the twelfth character (third zone) has been input. When the characteristic parameter is the resistance of the member, the fifteenth, sixteenth,
The number input to each of the seventeenth characters indicates the reference value of this characteristic parameter. In this case, this number consisting of three numbers is an average temperature of 20
It represents the resistance value of the member (sleeve) at ° C. Example 12th character = 1 15th-16-17 character = 300 It can be seen that these are R: 300Ω (ohm). The information entered in this fifth zone can correspond, in particular, to the average value of the parameters generally obtained during manufacture or to the theoretical value which serves for the probability of the "control" value used for ascertaining the parameters of the component as described below. If several 000 are entered in this zone,
This shows that the characteristic parameter R is not considered. Sixth Zone In the sixth zone consisting of the eighteenth character of the barcode, information relating to the characteristic character having the numerical value defined for the fifteenth, sixteenth, and seventeenth characters (fifth zone) is input. The value of the eighteenth character is calculated by combining the theoretical value of the characteristic parameter originally entered on the card with its "actual" value obtained from the detection of the member temperature by a thermal probe or from a controlled internal calculation at the level of the calculation unit. Error tolerances or tolerances in between that are accepted by the programming or control means of the device can be indicated (see note). In this example, since the characteristic parameter is R (the resistance of the member or sleeve), the internal calculation of the "actual" value is based on the theoretical value of the parameter R and the value of R measured by external means (especially an ohmmeter). Perform based on comparison. If the difference between the actual value and the theoretical value of the parameter is included in the information "allowable tolerance" of the eighteenth character, the programming means of the device does not consider the difference and supplies the theoretical value supplied when reading the zone. Operate based on On the other hand, if the tolerance is exceeded, the welding operation is stopped. Example Numbers and corresponding% for this 18th character level 1 = ± 6% 2 = ± 8% 3 = ± 10% 9 = see note 0 = don't consider% depends on “site” temperature Created in consideration of resistance change. Note: In the case of the number 9 In this case, no direct measurement of the actual temperature of the component by external means (thermal sonde) is made, instead the 20 ° C. entered in zone 5 (associated with zone 3) on the device. The said temperature is calculated by comparing the theoretical value of the resistance at the temperature of the component with the actual value of the resistance measured at the temperature of the component, for example by means of an ohmmeter. Therefore, the temperature parameter is obtained indirectly. Seventh Zone The seventh zone includes the nineteenth, twentieth, and twenty-first characters. The numerical value of the character represents the heating time of the member. Time can be indicated in seconds. For example, numbers 003 to 899 are used. The 19th, 20th and 21st characters are 10
Represents units of 0, 10 and 1 second. Time can also be indicated in minutes. In this case, 90
Use numbers from 0 to 999. In this case, the nineteenth character of the nineteenth character is meaningless. The twentieth and twenty-first characters represent units of 10 minutes and 1 minute, respectively. In the case of a predetermined numerical value (for example, 000), the heating time (or welding time) is not specified in the barcode. In this case, the interruption of the welding operation is controlled by an external sensor which stops the function of the device when the desired temperature is reached. Eighth Zone The eighth zone includes the 22nd and 23rd characters of the barcode card. This zone is used to modify the energy supplied from the power supply. In the present case, the parameter to be modified is the heating time or the heating power, which modification depends on the calculated or sensed material temperature at the thermal probe. By modifying the initial energy supply in this manner, a better level of welding quality can be maintained, regardless of weather conditions. The actual operation is as follows. If the temperature detected by the sonde is about 20 ° C, no correction is made. If below 20 ° C., define a positive correction percentage of the time or power parameter for each 1 ° C. If the temperature is 20 ° C or higher, the correction parameters of the initial parameters are determined for each 1 ° C. The time or power parameter to be modified is
This is selected when the numerical value of the third character (first zone) is assigned (see the description of the first zone). Example 1. 22nd character: Numerals 2 to 9 23rd character: Numerals 2 to 9 The digitized information on heating time or heating power contained in the above character represents 10% units per 1 ° C of the correction. 2. 22nd character = 0 23rd character = 0 The information "00" indicates that there is no time or power modification to be considered. Therefore, the above parameters are not changed. In this case, temperature detection by a thermal probe is necessary. 3. 22nd character = 1 23rd character = 1 The information "11" indicates that the time or power adjustment is not performed. Also in this case, the above parameters are not changed or modified. In this case, no temperature detection or calculation is performed. Ninth Zone The ninth zone includes the 24th and 25th characters of the barcode (the 25th character is the last character). The twenty-fourth character indicates that all information has been read by the optical pen and was considered significant. The control scheme is well known and is not the subject of the present invention and will not be described here. Thus, from the above example, the method according to the invention is based on the auxiliary information entered in the corresponding zone of the bar code, in which case the heating (welding) energy adjustment mode (O, I, P, etc.) can be determined and the selected reference value can be controlled (see the above example for the resistance R of the sleeve). Therefore, the method according to the present invention can be collectively defined as shown in the following table.

Continuation of front page    (56) References JP-A-58-195214 (JP, A)                 JP-A-61-175022 (JP, A)                 JP-B-51-27543 (JP, B2)                 Published French Patent Application 2572326 (FR, A               1)

Claims (1)

(57) [Claims] In order to automatically control the temperature rise of a member having a heating electric resistor by a control device, a) disposing a heating control card including a plurality of zones occupying individual locations on said member; b. Some of the zones on the card (zones 1, 2, 3,
4,9) input at least operation data relating to at least a predetermined value of power supplied to the electric resistor, the operation data being used by the control device and being readable by reading means of the control device; Operating data in the card is collected by its reading means; d) auxiliary data indicating the physical state of the member at the start of the heating process, including the temperature of the member, is read from the member and input to the controller; e) A) correcting the expected value of the power supplied to the electric resistor as a function of the auxiliary data to obtain an appropriate corrected power; f) supplying the corrected power to the electric resistor to heat the member The operating data in step b) includes: a power supply to the electrical resistor according to a physical state of the member at the start of a heating process. Information (zone 8) for correcting the electric current, a correction of the current value (I) supplied to the electric resistance, a correction of the voltage value (U) supplied to the electric resistance, and a time for flowing a current to the electric resistance. (1) selection data (zone 1) for selecting a correction mode for determining whether to correct the power supplied to the electric resistor by any of the corrections described in (1), and a physical data including a resistance value of the electric resistor. Data (zone 5) relating to the expected values of the physical parameters and data relating to the permissible range relating to the physical parameters of the electrical resistor (zone 6) are also included. The power supplied to the electric resistor is corrected as a function of the auxiliary data obtained from the member and as a function of the correction information obtained from the card. Determining the actual value of the physical parameter of the electrical resistor at the beginning of the heating process, comparing the actual value to a predetermined value of the physical parameter of the electrical resistor and determining between them. Determining the difference, performing the heating operation if the difference is within the allowable range from the card, and stopping the heating operation if the difference is outside the allowable range, wherein the heating operation is stopped. How to control the temperature.